Evaluation of surface temperature uniformity of multi-zone ceramic heaters with embedded cooling channels for electrostatic chuck

Electrostatic chuck (ESC) is used to transport and fix semiconductors during semiconductor processing effectively. In addition, the wafer is heated and cooled by the ESC to control its temperature. Since the uniformity of the wafer surface temperature has a close relationship with the semiconductor yield, it is essential to find the optimal temperature uniformity conditions considering the heating and cooling regions of the ESC. Therefore, in this study, heat transfer characteristics were analyzed to consider the change in the heating power of each zone of heating elements and the coolant flow rate in an ESC. Furthermore, the temperature uniformity of the ESC was quantitatively compared according to the driving conditions using the temperature deviation and dimensionless factor. It was confirmed that a change in the coolant flow rate had no significant effect on the temperature deviation compared with a temperature change at the top surface of the ESC. Moreover, when different heating powers were applied to each zone, the temperature deviation was decreased, and temperature uniformity was improved. The temperature deviation increases with the operating temperature of the ESC. Therefore, to further reduce the temperature deviation, an analysis considering the shape change of the heating element is necessary.